Automatic weapons such as the 40 mm MK19 Grenade Machinegun are designed to use ammunition with a specific external envelope. The external dimensions of a sub-caliber projectile cartridge must be compatible with the weapon from which it is fired. The cartridge configuration must also withstand the forces encountered during weapon feeding and cycling.
Sub-caliber projectiles are typically used for applications such as inexpensive training ammunition and applications where reduced terminal effects or reduced target damage are desired. Conventional projectiles include sub-caliber training devices and ammunition for large caliber artillery, howitzers and tank guns. These applications are designed for single shot weapon mechanisms and do not address the full automatic weapon operation typical of machineguns such as the 40 mm MK19 Grenade Machinegun.
There is a great and still unsatisfied need for a sub-caliber projectile cartridge for use in automatic weapons. Exemplary sub-caliber projectile applications include non-lethal projectiles and sub-caliber projectiles, short range training ammunition, and low cost training ammunition.